37 Swedish women are suing a fertility app for unwanted pregnancies

Nearly 40 women in Sweden are suing the makers of a fertility and contraceptive app after they say it caused their unintended pregnancies.

Natural Cycles, a contraceptive app that has been certified in the European Union as a form of birth control, came under fire after 37 women visited Södersjukhuset hospital in Stockholm for abortions after using the app, Swedish website SVT reports.

The app works by measuring a woman’s basal body temperature and using an algorithm to figure out where a woman is in her cycle, according to the Natural Cycles website. Then, women are discouraged from having sex or encouraged to use a backup method of birth control during their fertile window, i.e. the time when they’re most likely to get pregnant.

Natural Cycles says on its website that its effectiveness is “comparable to other conventional methods,” noting that seven women out of 100 who use the method get pregnant during one year due to all possible reasons.

There are currently not contraceptive apps in the U.S. that are approved by the Food and Drug Administration, but some women use apps designed for fertility to help them avoid an unwanted pregnancy in the same way as Natural Cycles. However, doctors say this really isn’t a great idea.

Jonathan Schaffir, M.D., an ob/gyn from The Ohio State University Wexner Medical Center, agrees. “It’s a method of birth control but not the most reliable one,” he tells Yahoo Lifestyle. This method is often used by women who don’t want to use other means of birth control for religious, social, or cultural reasons or like the idea of a “natural” approach to birth control, he says. However, it relies on a woman’s menstrual cycle being reliable and predictable, which it often isn’t. “Even with women who do have that pattern, sometimes a stressful month or an illness will throw things out of whack,” he says.

Jessica Griger, a spokesperson for fertility app Daysy, tells Yahoo Lifestyle that while some women may choose to use the app to help prevent an unintended pregnancy, it’s not designed or FDA approved to be used this way. “Daysy is not a contraceptive,” she says. “It identifies the days in which unprotected intercourse could lead to a pregnancy but it’s up to the user what she does with that information.” If used effectively, however, Daysy is 99.3 percent effective at accurately determining a woman’s fertility window, Griger says.

Tia Newcomer, president and COO of fertility app Kindara, tells Yahoo Lifestyle that people who use her company’s app report “predominantly” using it to try to conceive. However, she says, “Kindara has always remained devoted to giving women the tools, knowledge, and support to understand how their fertility works, take ownership of their reproductive health, and meet their fertility goals.” The app is “intended to help women better understand their cycles and simplify the fertility awareness-based methods charting process,” she adds.

If you’re set on using this method of birth control, it’s important to take into account the fact that it’s “not really effective as a whole,” Jessica Shepherd, M.D., a minimally-invasive gynecologist at Baylor University Medical Center at Dallas, tells Yahoo Lifestyle. If you have consistent menstrual cycles and would be OK with getting pregnant if things didn’t work right, it might be the method for you. “I’ve seen women who follow it well and it works well for them,” Shepherd says. “But it’s hard to say if it’s going to work for one woman in particular.”

If you follow this method of birth control and you don’t want to change it, just be aware of this: There’s a joke out there that people who use this method are called parents.